The hormone diffuses across the membrane and binds its receptor in cytoplasm or nucleus.

The hormone-receptor complex binds to response elements in the promoters and enhancers of genes.

This stimulates transcription.

The mechanism for steroid hormones is also used by:

Retinoic acid (vitamin A)

Thyroid hormones

Calcitriol (vitamin D)

Testicular feminization is caused by

A defective androgen receptor

Androgen

Steroid hormone that stimulates or controls the development and maintenance of male characteristics

Coffee inhibits

Phosphodiesterases (breaks phosphodiester bonds)

A hormone receptor must do what when bonded by a signal molecule

It must change conformation on the cytoplasmic or nuclear side

Water soluble hormones must deliver their message where

To the cell surface

Cyclic AMP is synthesized

From ATP and degraded to AMP

GENE EXPRESSION IS REGULATED BY

PHOSPHORYLATION OF THE TRANSCRIPTION FACTOR CREB

A receptor protein always has how many alpha helices that span the membrane

7

Once the GDP attaches to the receptor

It changes to GTP (its active state)

How does the GTP prevent from continually sending a signal once it has been triggered

The alpha sub unit turns it off once it binds, turning it back to GDP by hydrolysation

What is the cascade of the cyclic AMP signaling pathway

1. A receptor is activated by a signal

2. The G protein is activated

3. G protein activates Adenylate Cyclcase

4. The G protein stops itself from signaling further

5. The cyclic AMP activates the protein kinase

6. The protein kinase goes around phophorilating proteins

Inhibition of adenylate cyclase

Is pretty much the same cascade as activating only the G protein inhibits the Adenylate cylcase instead of activating it. Both are functioning in the cell at the same time, one just is simply functioning at a higher rate

What if there was no inhibition

Then the cyclase would continue to happen without stopping

Adenylate cyclases are triggered by what

The alpha subunit of the G protein

Cyclic Amp mediates the effects of many

Hormones

Cyclic adenosine monophosphate (cAMP, cyclic AMP) is

A second messenger important in many biological processes

What is Hormone resistance

When a patient has the hormones, but the effects of the hormones are absent

Pseudohypoparathyroidism

Patient has signs of chronic PTH (parathyroid hormone) deficiency: hypocalcemia, tetany. But the PTH level is normal or elevated.

Some patients have mutations in the PTH receptor. Others have an abnormal Gs protein that makes inefficient coupling with adenylate cyclase.

Toxic Thyroid Nodules

These are benign tumors in the thyroid gland that overproduce the hormones.

Cause: Some patients have an activating somatic mutation in the gene for the TSH receptor. Others have an activating mutation in the Gs protein that keeps it constitutively active, usually by blocking its GTPase activity.

TSH (Thyroid stimulating hormone) from the pituitary gland stimulates

Hormone production and cell proliferation in the thyroid gland by raising cAMP.

Cholera toxin

This is an intestinal infection by vibrio cholerae. The bacteria do not invade the tissues, but cause watery diarrhea through a secreted protein toxin.

What happens in cholera toxin

The toxin enters the cells, and catalyzes the covalent modification of the α-subunit of the Gs protein. This abolishes the GTPase activity of the Gs protein, leaving it in the active state permanently.

cAMP will accumulate

Pertussis toxin

Whooping cough:

Caused by Bordetella pertussis, which lives on the respiratory epithelium. One of its virulence factors is pertussis toxin.

Pertussis toxin mechanism

It modifies the α-subunit of the Gi protein. This inactivates the Gi protein.

Resting calcium is always in what portions of the cell

Low in the cytoplasm

High in ER and mitochondria

What is IP3 and DAG

Secondary messengers, molecules used in signal transduction and lipid signaling in biological cells. While DAG stays inside the membrane, IP3 is soluble and diffuses through the cell

Elevations of cytoplasmic calcium can be by

Hormones acting through a G-protein and IP3

A ligand-gated ion channel

Voltage-gated calcium channels

Intracellular calcium receptors include:

Protein kinase C

Calmodulin

Troponin C

Muscle contraction is always triggered by calcium, but the mechanisms are different in striated muscle and smooth muscle. What is the difference

The cascades that are induced by growth factors are out of control in cancer cells. Therefore the best approach for cancer treatment would be a drug that

Inhibits Akt (Protein kinase B)

PTH causes most of its biological effects by stimulating the production of cAMP, the most likely mutation in a patient who has signs of PTH deficiency (hypocalcemia, Tetany,) but an elevated PTH level is

A Gs alpha subunit with a reduced affinity for the PTH receptor

The best way to reduce the cAMP level in the intestinal mucosa is by

Smoke Opium

How do the second messengers DAG and IP3 differ from the cAMP mechanism

1. The GTP Complex cleaves to Phospholipase C

2. Phospholipase C forms DAG and IP3

3. DAG stays in the membrane and activates Protein Kinase C (PKC)

4. IP3 diffuses across the cytoplasm and opens calcium channels in the ER

DAG is short for

Diacylglycerol

PKC is short for

Protein Kinase C

cAMP is triggered by what hormone in the Liver inducing Glycogen breakdown

Glucagon

cAMP is triggered by what hormone in the Adipose tissue inducing Fat breakdown

Epinephrine Beta receptors

cAMP is triggered by what hormone in the Bronchial Smooth muscle inducing Relaxation

Epinephrine beta receptors

cAMP is triggered by what hormone in the vascular smooth muscle inducing Relaxation

Epinephrine beta receptors

TSH does what to the Thyroid gland

Triggers Hormone synthesis

ACTH does what to the Adrenal Gland

Triggers Hormone synthesis

MSH and ACTH does what to the Melanocytes

Triggers Melanin synthesis

Diarrhea is induced by what hormone in the intestines

Pancreatic polypeptide

Opiods do what to the brain and Intestines

Cause constipation in the intestines, and Analgesia (the loss of sense of pain) in the brain

Alpha 2 receptors do what to the brain

Cause hypotension

Somatostatin has what effect in the pituitary gland

Inhibition of growth hormone secretion

Melatonin has what effect in the melanocytes

It inhibits melanin synthesis

The endothelial cells can act as a vasodilator of vascular smooth muscles when triggered by what

Acetocholine

Bradykinin

Histamine

What do endothelial cells release to the smooth muscle causing dilation

NO which turns GTP to cGMP triggering the response

Epinephrine and Prostacyclin trigger what for relaxation in the vascular smooth muscle

Conversion of ATP to cAMP

A specific β-adrenergic receptor kinase that phosphorylates only the activated receptor is